The Statistical Analysis Core will provide high quality, integrated collaboration in and support of the proposed Center on the role of sex differences on progesterone and impulsivity in cocaine and nicotine addiction. As a foundation for all three proposed projects, this Core will provide: personnel with the appropriate breadth and depth of expertise; services in study design, study logistics planning, data management, and statistical analysis; training and mentoring; and other resources as needed. Core personnel will actively participate with project teams before study initiation, during study execution, and as part of novel cross-project initiatives that will integrate the projects to provide innovative insight into sex differences, progesterone, impulsivity, and addiction. This Core will in particular interact closely and extensively with the Science and Training Core (Core B) and the Administrative Core (Core A) on scientific and management oversight of each project as it is carried out, on the prioritization of SAC work across the needs of the projects, on the ongoing training and mentoring of junior investigators and trainees, and on supporting future research and funding opportunities on sex differences in addiction which are motivated by this proposed Center. Our continuity of involvement, from initial study planning through study completion and into dissemination, will provide a common connection among the projects spanning the entire proposed period. Lastly, we will provide resources for additional exploratory analyses that come to light as the research progresses, taking full advantage of the Center's careful data collection and management, thereby also facilitating the development of innovative hypotheses for future research.